UTP category 5 cable is a data or communications cable constructed of 4 unshielded twisted pairs of 24 AWG thermoplastic insulated conductors enclosed is a thermoplastic jacket. The pairs of copper wires are tightly twisted to achieve high speed transmission; the tighter the twist, the faster the possible transmission speed. While UTP is available in Category 3, 4, 5, or 6, the higher the number, the tighter the twist. The tighter the twist also helps reject electromagnetic interference. While many designers have selected category 3 for voice, and category 5 for data, the trend is to install category 5 or higher for all applications in commercial buildings. Other high performance cables are being developed.
As the computer and communications industries have grown, the organization and management of the cabling has become a serious problem. It has literally been dumped on the floor or dropped through walls, kinked around corners, or simply dropped on or dragged over the top of suspended ceilings. Cables such as UTP cables and fiber optic cables simply cannot be treated in such a cavalier fashion and have the equipment they serve meet expectations.
For example cross-talk on a telephone may be due to improper cabling or cable placement. Attenuation, cross-talk, data distortion, and return loss all affect signal strength which can degrade any system transmission capability. Attenuation is the loss of power or signal strength along the transmission medium. Cross-talk is an unwanted transmission from another nearby cable, or even a pair in the same cable. Return loss is a measure of degree of impedance between the cable and a connector. Background noise is also an irritating problem resulting from a low signal-to-noise ratio. Inadequate cable installation is a key reason for such factors, especially when data and voice transmission speeds are continually being increased, for example from 16 Mhz to 100 Mhz or more.
Such cable should not be kinked, snaked, bent sharply, tugged, sag excessively, or come into engagement with sharp edges, or be too close to power cables.
The wiring can be placed under the floor with elevated flooring which is extremely expensive and often not practical. A more common place for such wiring is above the ceiling between the structural floor or roof above, and a dropped or acoustical ceiling.
The area above many acoustical or drop ceilings is usually cluttered with structural members such as beams or open joists, utilities such as plumbing or sprinkler systems, HVAC ducts, conventional power wiring, often encased in conduit or armored, and of course the suspension hangers for the ceiling and any lighting or other fixtures in the ceiling.
Moreover, most beams, joists and other structures extend in a rectilinear fashion above a ceiling, while communications or data cable usually radiates from a panel or closet in a star topology.
Conventional power wiring clips, snaps, wire hooks, bridle rings, or plastic ties are not suitable for such cable because of a variety of factors. They may present sharp edges or produce sharp turns or kinks in the cabling, or they may crush or pinch a bundle.
One specialized support for such telecommunications cable is shown in applicants prior U.S. Pat. No. 5,740,994 which can be attached to a variety of building structures above a suspended ceiling or even supported to extend upwardly from a ceiling grid. Such support is sold by Erico Inc. of Solon, Ohio under the trademark CABLECAT™.
If the building is being built new and is being designed with such cable in mind, cable trays are often employed. These are simply suspended or cantilevered trays in which such cable can be laid flat to extend horizontally, and are hung or suspended from beams, joists, or decking for example, oftentimes by trapeze hangers. Such trays are expensive and can be retrofitted into existing building, but not easily or economically, particularly if there is not a significant amount or extent of open or unobstructed horizontal space.
More conventional cable tray clamps and hardware for both power and communication cables are sold under the well known CADDY® trademark. CADDY® is a registered trademark of Erico International Corporation of Solon, Ohio. These trays require a substantial amount of hardware and are best installed as the building is being constructed and before any acoustical or suspended ceiling is installed. Also such cable tray systems are more easily installed parallel to a structural member such as a beam, or transversely as with the aid of a trapeze. Flexibility and retrofitability are not particularly characteristic of these conventional cable tray systems.
Somewhat more flexibility is achieved with wire grid trays or systems. These still are costly and require a number of parts, and cannot be retrofitted above an existing ceiling without substantially dismantling the ceiling. They are more costly, more costly to install, and more costly to retrofit above an existing drop ceiling.
Traditional cable trays are usually made up of rigid aluminum or steel tray sections, which come in varying lengths that are connected together and attached to the building structure, while the newer “flexible” cable trays are predominately made up of wire-form cross sections that, again, come in varying lengths. Both types share a similar disadvantage, in that the lengths provided are difficult to manage, and practically impossible to install over an existing drop ceiling without removing entire sections of the T-grid and cross brace system. In addition, splices may require the installer to use several different tools to complete the splice, making them complicated and time-consuming to install.
One flexible wire form system indicates it can create any angle or avoid any obstacle with a pair of bolt cutters. This is hardly the type of tool which can be used easily, if at all, above a suspended ceiling without dismantling the whole ceiling.
Also, such wire form systems may be supported in the center of the wire form tray. Thus for symmetrical loading there may be two bundles or sets of cables, one on each side of the center support. One has to be loaded from one side while the other from the other side. This makes changes, additions, or transitions to the system more difficult.
Accordingly, it would be desirable to have a flexible support and distribution system with few parts which could be installed above an existing ceiling without substantially dismantling the ceiling, and which provides easy access to the entire width of the support and distribution system from one side.